Aqueous aerosol compositions for delivery of atomized oil

ABSTRACT

Aqueous aerosol compositions are produced particularly for the delivery of an atomized oil, such as a fragrance oil, insecticidal oil or medicinal oil. The water based system, which includes a water soluble propellant and a dispersed oil phase in water with a polymeric emulsion, does not need shaking before use, is not flammable, and leaves no deposition on surfaces.

TECHNICAL FIELD OF THE INVENTION

This invention is directed to aqueous aerosol compositions, particularlyfor the delivery of an atomized oil such as a fragrance oil,insecticidal oil and medicinal oil.

BACKGROUND OF THE INVENTION

In the past, different aerosol formulations have been used to deliveratomized oil particles. One type of aerosol composition contained anoil, co-solvent and propellant typically for dispensing a small amountof an oil, such as a perfume. A second type of aerosol used simply anoil and propellant. These aerosols were called dry systems because thecomponents vaporized upon spraying. A third type of aerosol is anaqueous based system which complies with EPA Regulations for VolatileOrganic Compounds (VOC) primarily because they have water as the majorcomponent. One of the major problems with an aqueous aerosol has beenthe need to shake the system before use, just as when one mixes oil andvinegar they separate, the same thing occurs with this system.Typically, a “shake before using” statement is on the label of theseproducts to avoid spraying only one phase through the dip tube of thespray can while the other phase remains in the can. In many cases, it isnot practical or possible to shake the container before use and, thus,these systems have limitations. Where room air fresheners are formulatedemploying the three types of aerosols, usually about 25-50% of a perfumeis contained in the first type, about 2-10% perfume is contained in thesecond type, and the third type usually contains about 1% perfume.

Two main types of water-based aerosols have been known, namely, athree-phase system and a two-phase system. The three-phase aerosolsystem is formed when using a propellant such as propane or butane whichis insoluble in the water phase. These three-phase aerosol systems needto be shaken properly before use. Two-phase aqueous aerosol systemsconsist of a homogeneous liquid phase and a gaseous phase. The liquidphase usually contains the active ingredients, solvents and liquifiedpropellant. Homogeneity is achieved by means of a water solublepropellant such as dimethyl ether (DME). These types of aerosols neednot be shaken before use. However, it has been difficult to obtainhomogeneous DME-water mixtures which are stable upon standing. Attemptshave been made to solve the stability problem by developing specialperfumes or by the addition of special solvents. U.S. Pat. No. 4,382,078is an example of a prior approach to solve the stability problem byemploying a copolymer of ethylene oxide and propylene oxide as asurfactant to retain the active ingredients in the liquid phase.

Furthermore, in this '078 patent, with increasing amounts of fragranceoil, increasing amounts of surfactant are required. Increased surfactantresults in non-volatile material being sprayed which is undesirablebecause of unwanted deposition on surfaces, among other environmentaldeficiencies.

There exists a need for an aqueous aerosol composition for the deliveryof atomized oil such as a fragrance oil, insecticidal oil and medicinaloil without the disadvantages associated with presently availablesystems.

SUMMARY OF THE INVENTION

This invention is directed to an aqueous aerosol composition containingwater, water soluble propellant, dispersed oil phase in the water,nonionic surfactant and a polymeric emulsifier. The components of thecomposition are contained in relative amounts to provide a viscosity fordelivery of atomized particles of the oil.

In accordance with the principles of this invention, a water basedsystem is used to give a concentrated aqueous system that does not needshaking, is not flammable, and performs like a concentrated non-aqueoussystem. This invention is predicated in part upon the use of a polymericemulsifier that forms a matrix into which the oil can be trapped. Anonionic surfactant helps suspend the oil particles by decreasing thedroplet size of the dispersed phase in the water. A water solublepropellant, such as dimethyl ether has been found to provide thecomposition with satisfactory delivery of atomized oil particles. Theaqueous aerosol compositions of this invention have been found toprovide substantial stability on standing for many months. Furthermore,atomized particles are delivered by the compositions without beardingand with a consistent spray pattern during the life of the product. Incontrast to other water-based aerosol systems, the compositions of thisinvention do not require shaking before use, notwithstanding the uniquethree-phase system of the polymer matrix, oil and water. Heretofore,three-phase aerosol systems have required shaking before use. In thisregard, this is considered one of the unexpected advantages of thecomposition of this invention.

Another advantage of the aqueous aerosol compositions of this inventionis the ability to use varying amounts of oil from about 0.1% to about30% by weight while even employing one low level of polymericemulsifier. It has been found that a minor amount of polymericemulsifier, on the order of about 0.05% to about 0.4% by weight, iscapable of physically suspending or emulsifying significant amounts ofperfume in a three dimensional matrix and holds them there in what mightbe considered a thermodynamically unstable form. The oil particles aresurrounded by the surfactant which helps hold them in suspension. Inthis regard, very minor amounts of surfactant, on the order of onlyabout 0.1% to about 1% by weight, are necessary to hold the oilparticles in solution.

A water soluble propellant such as dimethyl ether and methylethyl etheris required in order to obtain the benefits of this invention. Inparticular, the aqueous solutions do not exhibit flame extensions, andaerosol containers using the system comply with VOC regulations (EPAregulations for Volatile Organic Compounds, Section 183(e), Clean AirAct, 40 CFR, Chapter 1, pages 48,792—48,887). Furthermore, the inventiveaqueous aerosol compositions perform at least at parity to thenon-aqueous aerosol systems. An amount of a hydrocarbon propellantselected from the group consisting of propane, isobutane, butane, andmixtures thereof, may be employed with the water soluble propellant.When so employed, the hydrocarbon propellant is usually contained in anamount of from about 50% to about 20% by weight of the water solublepropellant, such as dimethyl ether.

Other advantages and objectives of this invention will be furtherunderstood with reference to the following detailed description.

DETAILED DESCRIPTION

A preferred aqueous aerosol composition of this invention and a range ofcomponents that may be satisfactorily employed is illustrated by thefollowing table.

Preferred Amount Range Component (% by weight) (% by weight) Propellant28 about 20 to about 40 Dimethyl ether (DME) Perfume 4 about 0.5 toabout 30 Polymeric emulsifier 0.18 0.0.05-0.40 Pemulen 1622 DisodiumEDTA 0.036 0.01-0.06 Pluronic 10R5 surfactant 0.36 0.1-1.0Triethanolamine (TEA) 0.27 0.05-0.45 Viscosity modifier 0.36 0.05-0.45Goodrite 752 Water 66.8 balance

Pemulen 1622 is a polymeric emulsifier made by B. F. Goodrich and isdescribed as a copolymer of acrylic acid and C_(10—30) alkyl acrylatecross-linked with polyalkenyl ether. More generically suitable polymericemulsifiers according to this invention are selected from the groupconsisting of polyacrylic acid homopolymer and copolymers thereof suchas Pemulen 1622 which is a copolymer of a polyalkyl acrylate. Thedisodium ethylene diaminetetraacetic acid (EDTA) is employed to complexmetal ions which may otherwise destabilize the emulsion. Pluronic 10R5is a block copolymer of ethylene oxide and propylene oxide which isemployed as a surfactant. Other surfactants that are suitable includenonylphenol polyoxyethylene, ethyoxylated alcohol and polyoxyethylenesorbitan monooleate. Triethanolamine is employed to adjust and stabilizethe pH of a composition. Goodrite 752 is a viscosity modifier, also madeby B. F. Goodrich, and is described as a water soluble polyacrylic acidor polymethylacrylic acid, and copolymers thereof, typicallycopolymerized with a sulfonic acid and a styrene sulfonate. The abovecomponents are thus provided in relative amounts to provide viscosityadjustments for the delivery of atomized particles of the oil.Satisfactory viscosities for room air freshening, for example, are onthe order of about 200-400 cp at 25° C., Brookfield RVT @ 20 rpm, #2spindle.

One method of making the presently preferred aqueous aerosol for use asan air freshener employing the specific components of Table 1 involvesfirst stirring the Pemulen 1622 in water to completely hydrate thepolymeric emulsifier to form a stable dispersion. Minor amounts ofPemulen, from about 0.5% up to about 0.4% by weight, are employed toachieve a stable dispersion without producing a product which becomeslike molasses and is difficult to spray. Fragrance oil is then added,preferably avoiding air, in order to capture the oil in the polymericemulsifier matrix to form a macro emulsion with the fragrance oilcontained in the form of a physical emulsion in the matrix. The Pluronic10R5 is then added to coat the fragrance oil particles and decrease theparticle size to provide a storage stable product. The disodium EDTA isadded to capture ions which would tend to destabilize the emulsion, andtriethanolamine is added to neutralize the carboxylic acid groups on thepolymer matrix of the emulsifier. At this point in the processing, amilky liquid having a viscosity of about 800-1500 cP is obtained(Brookfield RVT @20 rpm, #2 spindle). In order to reduce the viscosityto an acceptable level for practical room spraying, the Goodrite K752 isadded to decrease the apparent viscosity to about 200-400 cP. The finalcomposition is then placed in a can and the DME is forced into the canto achieve an equilibrium pressure inside the can of about 67 psig at70° F. Room spray is delivered from the can at about 0.49 gms/sec, whichis consumer acceptable.

Any perfumes may be employed as air fresheners to provide such odors aswoody, fruity, spicy, earthy, and the like. As mentioned above, the oilsmay be any one of a member of a class of oils described as insecticides,silicones, medicinal agents, and the like. In view of the above detaileddescription and operating examples, a person of ordinary skill in theart will understand that other modifications and embodiments may bederived without departing from the spirit and scope of this invention.

What is claimed is:
 1. An aqueous aerosol air freshener for roomspraying composition for the delivery of atomized particles of oilcomprising water, a water soluble propellant selected from the groupconsisting of dimethyl ether and methylethyl ether, about 0 to about 30percent by weight of a dispersed oil phase in the water, a nonionicsurfactant and about 0.05 to about 0.4 percent by weight of a polymericemulsifier selected from the group consisting of polyacrylic homopolymerand copolymers thereof, said components in relative amounts to provide aviscosity for delivery of atomized particles of the oil.
 2. Thecomposition of claim 1 wherein the copolymer is a polyalkylacrylate. 3.The composition of claim 1 wherein the nonionic surfactant is selectedfrom the group consisting of a block copolymer of ethylene oxide andpropylene oxide, nonylphenol polyoxyethylene, ethyoxylated alcohol, andpolyoxyethylene sorbitan monooleate.
 4. The composition of claim 1further containing a water soluble polymer as a viscosity modifier. 5.The composition of claim 4 wherein the water soluble polymer is selectedfrom the group consisting of a water soluble polyacrylic acid,polymethylacrylic acid, and copolymers thereof.
 6. The composition ofclaim 1 further comprising a hydrocarbon propellant selected from thegroup consisting of propane, isobutene, butane, and mixtures thereof inan amount of from about 50 to about 20 percent by weight of said watersoluble propellant.
 7. An aqueous aerosol air freshener for roomspraying composition for delivery of atomized particles of a fragranceoil consisting essentially of about 20% to about 40% by weight dimethylether propellant, about 0.5% to about 30% by weight fragrance oil, about0.05% to about 0.4% by weight of a polymeric emulsifier selected fromthe group consisting of polyacrylic homopolymer and copolymers thereof,a nonionic surfactant, a pH modifier, a viscosity modifier, and thebalance water.
 8. The composition of claim 7 wherein the surfactant is ablock copolymer of ethylene oxide and propylene oxide in an amount offrom about 0.1% to about 1% by weight, and the viscosity modifier is awater soluble polyacrylate polymer in an amount of from about 0.05% toabout 0.45% by weight.
 9. The composition of claim 8 further containinga chelating agent and a pH modifier.
 10. The composition of claim 8further containing a hydrocarbon propellant selected from the groupconsisting of propane, isobutant, butane, and mixtures thereof, in anamount of from about 50% to about 20% by weight of said dimethyl ether.11. An aqueous aerosol air freshener for room spraying composition fordelivery of atomized particles of oil consisting essentially of about20% to about 30%, by weight dimethyl ether propellant, about 0.5% toabout 30% by weight oil, about 0.05% to about 0.4% by weight of apolymeric emulsifier selected from the group consisting of polyacrylichomopolymer and copolymers thereof, about 0.05% to about 0.45% by weightof water soluble polyacrylate polymer as a viscosity modifier, about0.1% to about 1% by weight of a block polymer of ethylene oxide andpropylene oxide, about 0.01% to about 0.06% by weight of disodium EDTA,about 0.05% to about 0.45% by weight of triethanolamine pH modifier, andthe balance water.
 12. The composition of claim 11 wherein the oil isselected from the group consisting of a fragrance oil, insecticidal oil,medicinal oil, and silicone oil.